Spectral imaging of kimberlite drill core for mineral mapping

金伯利岩是一组富含挥发分(主要是二氧化碳)的钾质超镁铁质火成岩，其中可以含有作为副矿物的钻石。在世界范围内，只有不到1%的金伯利岩含有足够数量的钻石，这些钻石在经济上是可行的。金伯利岩的特征是具有明显的不均匀结构，这是由于存在巨晶和/或巨晶(主要是橄榄石)，它们被放置在更细的基质中。钻石的浓度，即单个金伯利岩矿体内的钻石等级，在短距离内可能有很大差异，这使得有效的开采过程具有挑战性。金伯利岩的结构及其矿物成分的模式丰度对钻石等级有很大影响。因此，为了可靠地预测钻石品位，以高空间分辨率准确地确定金伯利岩中矿物组分的模式丰度是有价值的。在这一过程中，必须特别强调与钻石有遗传联系的矿物相(如地幔橄榄石巨晶)与导致金伯利岩矿石稀释的矿物/岩石成分(如围岩包体)之间的区别。为了辅助这一点，我们建议使用反射光谱成像技术。利用可见光、近红外和中红外波长，我们的目标是使用金伯利岩钻芯的反射成像光谱创建准确的矿物地图图像。这些图像将被用来识别和标记不同的金伯利岩相，并帮助进行钻芯的等级评估。

Kimberlites are a group of volatile-rich (primarily CO2) potassic ultramafic igneous rocks, which can contain diamonds as an accessory mineral. Worldwide, less than 1% of the kimberlites contain diamonds in sufficient quantities to be economically viable. Kimberlites are characterized by a distinctly inequigranular texture, which results from the presence of macrocrysts and/or megacrysts (primarily olivine) that are set in a finer-grained matrix. The concentration of diamonds, i.e. the diamond grades within a single kimberlite ore body can vary substantially over short distance, which makes an efficient extraction process challenging. Diamond grades are greatly influenced by the texture of a kimberlite and by the modal abundance of its mineral constituents. For a reliable prediction of the diamond grade, it is, therefore, valuable to determine the modal abundance of the mineral components within a kimberlite accurately and with high spatial resolution. In this process, particular emphasis has to be put on the distinction between mineral phases that are genetically linked to diamonds, such as mantle-derived olivine macrocrysts, and mineral/rock components that cause a dilution of the kimberlite ore, such as country rock xenoliths. To assist with this, we propose using reflectance spectroscopy imaging technology. Using visible, near-infrared, and mid-infrared wavelengths, we aim to create accurate mineral map images using reflectance imaging spectroscopy for kimberlite drill cores. These images will be used to identify and label different kimberlite facies, and assist with the grade assessment of the drill core.